This section provides background information related to the present disclosure which is not necessarily prior art.
Organic Light-Emitting Diode (OLED) display device is a display device having self-luminous function. Because it needs no backlight source and has advantages like high contrast, small thickness, wide viewing angle, fast response, high-low temperature resistance, etc., it has a broad prospect in the display industry.
An OLED display device typically may include a display substrate, which comprises a base substrate, and three light emitting units superposed sequentially on the substrate. By way of example, the three light emitting units comprise: a red light unit, a green light unit and a blue light unit, each light emitting unit including: a cathode layer, an organic light emitting layer and an anode layer superposed sequentially. The base substrate is typically a glass substrate; the cathode layer is usually a metal film layer or Indium Tin Oxides (ITO) transparent conductive film layer; the anode layer is usually an ITO transparent conductive film layer; and the organic light emitting layer is an OLED light emitting layer.
Since the refractivity of the anode layer and of the organic light emitting layer is greater than the refractivity of the base substrate and the refractivity of the base substrate is greater than the refractivity of air, light emitted from the organic light emitting layer easily take place total reflection at the interface between the anode layer and the base substrate and the interface between the base substrate and the air, not easily exits the base substrate, whereby the display substrate and the display device comprising the display substrate have a low light outgoing efficiency.